SPECTRUM can be programmed with "command-line switches" to give a number of different outputs. In the default mode, SPECTRUM computes the stellar-disk-integrated normalized-intensity spectrum, but in addition, SPECTRUM will compute the absolute monochromatic flux from the stellar atmosphere or the specific intensity from any point on the stellar surface.
SPECTRUM and a number of auxiliary programs can be run under batch mode, making automated computation of a large number of synthetic spectra possible.
SPECTRUM is distributed with an atomic and molecular line list for
optical spectral region 3000 A to 6800 A, called luke.lst,
for computing synthetic spectra for stars with effective temperatures
between about 4500K
20,000K. Further line lists in the ultraviolet, the near infrared
and the infrared
(out to 4 microns) are also available.
SPECTRUM currently supports all naturally occuring atomic elements,
including 308 isotopes,
and their first and in most cases second ions, and for specific
elements, the third and fourth ions. SPECTRUM also supports the
diatomic molecules (including a number of isotopic versions): H2,
CH, NH, OH, MgH, SiH, CaH, SiO, C2, CN, CO
TiO. Other molecules and ions will be added in the future.